制作PPT的7种武器

WELDDEFECTSWELDDEFECTScracksslaginclusionsinclusionsporosityexcessiveorinadequatereinforcementimproperfit-up(misalignment)distortionundercutoverlaplackoffusioninadequatepenetrationCRACKSCRACKS(hi-lo)EXCESSREINFORCEMENTINADEQUATEREINFORCEMENTWELDEFECTSOverlapUndercutINTERNALUNDERCUTEXTERNALUNDERCUTWELDPROFILEDEFECTSExcessiveconvexityExcessiveconcavityLACKOFFUSIONLACKOFPENETRATIONWELDEXAMINATIONWELDINSPECTIONProperweldprocedure:Parentmetalandfillermetalarecompatiblethicknessesmethod(GTAW,SMAW,GMAW)position(horizontal,flat,vertical,overhead,all-position)jointpreparationheattreatmentQualificationsofwelders:whenlasttestedtoprocedureinquestionFit-upDefectsWELDINSPECTIONNDE:x-rayultrasoundmagneticparticledye-penetrantRADIOGRAPHICTESTINGSHELLSANDDRUMSAllboilerandpressurevesseljointsare“fullpenetration”weldsAfull-penetrationweldisaweldwheretheweldmaterialisdepositedthroughouttheentirethicknessofthematerialX-RAYSEachboilerweldjoint(withafewexceptions)requiresradiographicexaminationtoensurethequalityoftheweld.HEATTREATMENTWeldingcreatesstressinthe“heat-affectedzone”oftheparentmetal,resultinginbrittleness.Twotypesofheattreatmentforweld-inducedstress:preheatingPWHTpost-weldheattreatment(stress-relief)Stress-reliefisonlynecessaryoncertainthicknesses,materials,andpressuresBothmethodsworkbyallowingtheweldtocoolslower,sothedepositedmetalhastimetocrystallizeintoalow-stressmicrostructure.HEAT-AFFECTEDZONEHEATTREATMENTRADIOGRAPHYTheradiationusedinradiographytestingisahigherenergy(shorterwavelength)versionoftheelectromagneticwavesthatweseeasvisiblelight.TheradiationcancomefromanX-raygeneratororaradioactivesource.RADIOGRAPHYHighElectricalPotentialElectrons-+X-rayGeneratororRadioactiveSourceCreatesRadiationExposureRecordingDeviceRadiationPenetratestheSampleFILMRADIOGRAPHYTopviewofdevelopedfilmX-rayfilmThepartisplacedbetweentheradiationsourceandapieceoffilm.Thepartwillstopsomeoftheradiation.Thickerandmoredenseareawillstopmoreoftheradiation.=moreexposure=lessexposureThefilmdarkness(density)willvarywiththeamountofradiationreachingthefilmthroughthetestobject.RADIOGRAPHICIMAGESPENETRAMETERSPENETRAMETERSPenetrametersarealsocalled“Pennies”Theyshowifthex-rayhasproperexposureTheyshowifthex-rayhasproperfocus.RADIOGRAPHICIMAGESCanyoudeterminewhatobjectwasradiographedinthisandthenextthreeslides?RADIOGRAPHICIMAGESRADIOGRAPHICIMAGESRADIOGRAPHICIMAGESLIQUIDPENETRANTTESTING•Aliquidwithhighsurfacewettingcharacteristicsisappliedtothesurfaceofthepartandallowedtimetoseepintosurfacebreakingdefects.•Theexcessliquidisremovedfromthesurfaceofthepart.•Adeveloper(powder)isappliedtopullthetrappedpenetrantoutthedefectandspreaditonthesurfacewhereitcanbeseen.•Visualinspectionisthefinalstepintheprocess.ThepenetrantusedisoftenloadedwithafluorescentdyeandtheinspectionisdoneunderUVlighttoincreasetestsensitivity.LIQUIDPENETRANTINSPECTIONWHATMAKESPTWORK?•Everystepofthepenetrantprocessisdonetopromotecapillaryaction.•Thisisthephenomenonofaliquidrisingorclimbingwhenconfinedtosmallopeningsduetosurfacewettingpropertiesoftheliquid.•Someexamples:Plantsandtreesdrawwaterupfromthegroundtotheirbranchesandleavestosupplytheirnourishment.Thehumanbodyhasmilesofcapillariesthatcarrylifesustainingbloodtoourentirebody.BASICPROCESSOFPT1)Clean&DryComponent4)ApplyDeveloper2)ApplyPenetrant3)RemoveExcess5)VisualInspection6)PostCleanComponentULTRASONICTESTINGHighfrequencysoundwavesareintroducedintoamaterialandtheyarereflectedbackfromsurfacesorflaws.Reflectedsoundenergyisdisplayedversustime,andinspectorcanvisualizeacrosssectionofthespecimenshowingthedepthoffeaturesthatreflectsound.fplatecrack0246810initialpulsecrackechobacksurfaceechoOscilloscope,orflawdetectorscreenULTRASONICINSPECTION(PULSE-ECHO)